stream.h

// Copyright 2024 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
#pragma once
 
#include <cstddef>
 
#include "pw_multibuf/multibuf.h"
#include "pw_stream/stream.h"
 
namespace pw::multibuf {
 
class Stream : public stream::SeekableReaderWriter {
 public:
  Stream(MultiBuf& multibuf)
      : multibuf_(multibuf),
        iterator_(multibuf_.begin()),
        multibuf_offset_(0) {}
 
  constexpr const MultiBuf& multibuf() const { return multibuf_; }
 
 private:
  Status DoWrite(ConstByteSpan data) override;
 
  StatusWithSize DoRead(ByteSpan destination) override;
 
  Status DoSeek(ptrdiff_t offset, Whence origin) override;
 
  size_t DoTell() override { return multibuf_offset_; }
 
  size_t ConservativeLimit(LimitType) const override {
    return multibuf_.size() - multibuf_offset_;
  }
 
  MultiBuf& multibuf_;
  MultiBuf::iterator iterator_;
  size_t multibuf_offset_;
};
 
}  // namespace pw::multibuf